At 07:43 AM 5/15/00 -0700, you wrote:
I don't mean to be too discouraging; I think it's a good idea to go ahead
and do the best you can, but I think that until copies of the schematics
that described the TIA design surface so that somebody can tell us what they
really mean, an updated 2600 programmers guide will never be *complete*.
Joe Decuir is around. He was at CG Expo and will be there again. In fact,
last I emailed him he was still trying to free up time to work on a "how
does the 2600 work" voiceover presentation for Stella at 20: Volume
1. This information isn't yet lost to the ages.
It might not go into any more detail than some seasoned programmer here
might be able to do, but it's something.
There are too many undocumented tricks that have never been described
adequately.
I'm not sure they really have to be described on a raw IEEE level, although
it would be nice from an informational perspective. If they were
adequately described, I'm not sure software guys would know what to do with
the information. In fact, some of the information won't be useful because
it simply explains how internally the chip works but some of that stuff
isn't exposed to the software, so it's "hardwired". I think it's more
useful to describe observed _BEHAVIOR_ of the chips when driven by the
software. This has already been done through Stellalist to some extent
with the horizontal positioning system. We've looked a lot at how the TIA
reacts when these registers are hit at unorthodox times. We also don't
necessarily need to know how the poly counters are arranged at the logic
level in the TIA chip as much as we need that sound chart that gives us the
note and frequency values of all the possible 2600 sound tones.
For example, how does horizontal positioning *really* work. At
this point, outside of the guy who designed the chip (Joe Decuir), I don't
think anybody really knows.
Actually, there would be three living designers who knows. Joe, Steve
Mayer, and Ron Milner, but Joe is the most outgoing as far as interfacing
with the classic community. Next to that, I also think David Crane is
intimately familiar with the 2600 hardware.
Glenn Saunders - Producer - Cyberpunks Entertainment
Personal homepage: http://www.geocities.com/Hollywood/1698
Cyberpunks Entertainment: http://cyberpunks.uni.cc
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